1. Field of the Invention
The present invention relates to a multiple-barrel, repeating firearm. The firearm includes multiple bolts, equal in number to the number of multiple barrels, and includes a single lock-up mechanism capable of locking each of the bolts.
2. Description of the Background Art
Various repeating firearms are known in the prior art. Further, a firearm having two barrels and being capable of selectively firing two different types of ammunition is known, from my prior U.S. Pat. No. 4,867,039. U.S. Pat. No. 4,867,039 details a firearm with the capability of firing either shotgun shells or rifle cartridges in response to a positioning of a selector lever. Incorporation by reference is made to the disclosure of this patent for the purposes of explaining the structure and functioning of various firearm components, not improved by the present invention.
Multiple-barrel firearms, as well as single-barrel firearms, include a breech locking mechanism. The breech locking mechanism closes the breech of the barrel by securing a bolt against a chamber formed at the end of the barrel. In typical operation, a round of ammunition is fed, either manually or mechanically, into the chamber at the end of a gun barrel. Next, the bolt is moved to a position adjacent the chamber. The bolt contains a firing pin, which is aligned with a primer of the loaded ammunition. The bolt is locked by some type of breech locking mechanism, so that upon firing of the ammunition the bolt will be blocked against any rearward movement.
To fire the weapon, the firing pin is stuck by a hammer, or released from a spring tension, thereby firing the round of ammunition. After the ammunition is fired, the bolt is unlock and moved to a position remote from the chamber, so that the spent cartridge may be removed from the chamber, either manually or mechanically. At this point, the firing cycle is completed, and a new round of ammunition may be inserted into the chamber to begin a new firing cycle.
Several types of breech locking mechanisms are known in the background art. For example, U.S. Pat. No. 4,867,039 illustrates two independent, ball-lockup type breech-locking mechanisms. An upper breech locking mechanism operates in conjunction with the upper bolt for firing shotgun shells, and a lower breech locking mechanism operates in conjunction with the lower bolt for firing rifle cartridges.
FIGS. 10 and 11 illustrate the upper breech locking mechanism of U.S. Pat. No. 4,867,039, wherein a bolt 100 is seated to a chamber 101. A circular locking groove 102 is provided rearwardly of the chamber 101. The bolt 100 includes a plurality of balls 103. A breech locking mechanism 104 includes a forward curved end 105, which is brought to bear against inner portions of the balls 103. The balls 103 are pressed outwardly, into the groove 102, thereby locking the bolt 100 against any rearward movement.
After the ammunition round is fired, the breech locking mechanism 104 is moved rearwardly. The forward curved end 105 moves away from its engagement with the balls 103 of the bolt 100, thereby freeing the bolt 100 to move in the rearward direction. It should be noted that the components of the breech locking mechanism 104 are located rearwardly of the chamber 101. Furthermore, the actual locking of the breech, i.e. the balls 103 engaging into the groove 102, occurs rearwardly of the chamber 101 and forward face of the bolt 100.
U.S. Pat. No. 5,440,963 illustrates another well-known type of breech locking mechanism. FIG. 12 illustrates the breech locking mechanism wherein three locking lugs 200 are attached to a rear portion of a bolt 201. The bolt 201 is rotated so as to insert the three locking lugs 200 into three locking grooves 202 located in the receiver section 203. The engagement between the locking lugs 200 and the locking grooves 202 assures that the bolt 201 will not move rearwardly during firing of a round of ammunition.
After firing, the bolt 201 is rotated to free the locking lugs 200 from the locking grooves 202, so that the bolt 201 may be manually moved rearwardly for cartridge extraction and ammunition reloading. Again, it should be noted that the components of the breech locking mechanism are located rearwardly of the chamber, and therefore the actual locking, i.e. locking lugs 200 engaged into locking grooves 202, occurs rearwardly of the chamber and the forward face of the bolt 201.
All known breech locking mechanisms include a locking engagement which occurs rearwardly of the chamber and the forward face of the bolt. Such known, breech locking mechanisms take up space inside the receiver section of the firearm. The space inside the receiver section houses essential components of the firearm, such as the trigger assembly, safety, and ejection and feeding mechanisms. Moreover, in a multi-barrel firearm, as in the present invention, the receiver section space also accommodates a selector mechanism for choosing which bolt will be fired, as well as an additional set of extraction and feeding mechanisms. Therefore, the presence of the breech locking mechanism inside the receiver section complicates the design of the receiver section and/or requires that the receiver section have an enlarged volume.
Consequentially, there exists a need in the art for a breech locking mechanism, which requires a minimum amount of space inside the receiver section of the firearm.